Presently, resinoid bonded abrasive snagging wheels are limited to operating safely at a peripheral surface speed of 5029.2 meters per minute (16500 sfpm). Higher speeds have been attained with segmental wheels such as disclosed in the "Fifth Annual Report of the Grinding Wheel Institute Investigation of Grinding Fundamentals" April 1969, pages 6-1-6-36 and by Milton Shaw in U.S. Pat. No. 3,636,665 but none have been proved to be economically feasible.
It is also well known that the bursting strength of a grinding wheel can be increased by decreasing mounting spindle or arbor hole size up to the maximum where the wheel is "holeless". "Nohole" wheels of various configurations are disclosed in U.S. Pat. Nos. 1,918,392; 2,173,461; 3,367,068 and 3,780,476; British Pat. No. 451,781 and German Pat. No. 67,442. Solid center or holeless wheels were and are still being used to limited extent but are expensive to make and difficult to mount for rotation about their axis. Some of the solid center wheels disclosed in the above mentioned patents have either projections or recesses on one or both sides thereof engaged by opposing drive flanges of the spindle mounting. In some cases the flanges or studs are permanently fixed with adhesive to the sides of the wheel while in others the wheel is clamped between a pair of flanges at least one of which is adapted to be removed and displaced axially relative to the other.
Also known are a number of methods and materials whereby a grinding wheel may be reinforced against bursting and holding fragments of a burst wheel together to prevent injury to the workman and the apparatus. For example, the prior art teaches reinforced wheels having dense non-grinding inner central zones of either bonded abrasive or "non-abrasive" particles of finer grit size than used in the outer grinding zone, or a greater amount of bond holding the particles together than in the outer zone.
In addition, various organic and inorganic reinforcing material in the form of chopped or short continuous fibers, rods, webs, rings, wire mesh, cloth, having either twisted or untwisted continuous filaments and discs of woven or non woven fibers, continuous filaments or roving have been bonded to or molded within wheels. However, the reinforcement generally extends radially outward from and around the center of the wheel but did not pass continuously through the center of the wheel to opposite surfaces thereof.
U.S. Pat. No. 2,809,478 discloses a relatively small high speed grinding wheel of similar elongated shape with opposing arcuate grinding surfaces but has a conventional arbor mounting hole therein.